Method and system for multi-hop communication management in wireless communications networks

ABSTRACT

The present invention provides a wireless communication system capable of managing multi-hop communications. In one embodiment, upon receiving a request from a mobile terminal for initiating a call, the system determines whether the mobile terminal can use multi-hop communication services and its operating mode for multi-hop communication. The system also determines whether relaying can be provided by other mobile terminals. Then, the system will establish multi-hop communication between the mobile terminal and the system based on the operating mode of the mobile terminal. In a default mode, multi-hop communication can be established without the user&#39;s knowledge. In a prompt mode, however, the system sends a prompt to the mobile terminal for selection of the multi-hop communication services, along with information about incentives for using the services. After the multi-hop communication is completed, the system records information relating to the multi-hop communication services for the originating and relaying mobile terminals in the HLR/VLR.

BACKGROUND OF THE INVENTION

The invention relates generally to wireless communications systems, andmore particularly to method and system for multi-hop communicationmanagement in wireless communication networks.

Wireless communication networks become increasingly popular nowadays fortheir provision of ubiquitous computing capability and informationaccess regardless of the location. Currently, there are two types ofwireless communication networks: infrastructure-based wirelesscommunication networks, such as cellular phone networks, andinfrastructure-less wireless communication networks, such as ad hocwireless communication networks. In the infrastructure-based networks,the transmission range of a base station or an access point determinesthe size of a cell, and a mobile terminal within the cell cancommunicate directly with the base station or access point (in one hop).On the other hand, in the ad hoc wireless communication networks, themobile terminals are self-organized and can communicate with each othereven when they are out of the radio range of the base station or accesspoint, provided they can reach each other via intermediate mobileterminals that forward the data from the source terminal to thedestination terminal (in multi-hop). With their intrinsiccharacteristics, the ad hoc wireless communication networks have manypotential applications, such as in personal area networks, militaryenvironment and search-and-rescue operations. However, large, pure adhoc wireless communication networks are still far from deployment due tovarious technical and human limitations, while the infrastructure-basedwireless communication networks are already a huge success.

With the advantages of multi-hop communication capability offered by thead hoc wireless communication networks, the integration of multi-hopcapability in conventional infrastructure-based wireless communicationnetworks is a promising architecture upgrade that will help fulfill, toa large extent, the requirements of the very ambitious capacity,throughput, and coverage of the future wireless communication networks.

An infrastructure-based, multi-hop enabled wireless communicationnetwork provides many advantages. With relaying provided by one or moremobile terminals near a cell border, the cell coverage can be furtherextended. Moreover, relaying can improve signal quality whenline-of-sight link is not available and can reduce dead spots, which isparticularly important in emergency situations. In addition, sinceresearch shows the system capacity is inverse proportional to the totaltransmission power and the transmission power is inverse proportional tothe transmission distance to the n^(th) power, an increase in the numberof hops between the source and destination will result in a decrease inthe interference and thus an increase in the system capacity.

In recent years, various infrastructure-based, multi-hop enabledwireless communication networks, such as the Opportunity Driven MultipleAccess (ODMA) concept in 3 GPP, and the coverage extension for HIPERLAN2through multi-hop, etc., have been proposed. However, the multi-hoptechnology is far from being practically deployed because of manychallenges, especially the lack of a feasible multi-hop communicationmanagement scheme to attract the attention of both mobile operators andmobile users.

Therefore, there is a need for an effective scheme for managingmulti-hop communications in infrastructure-based wireless communicationnetworks.

SUMMARY OF THE INVENTION

The present invention provides an effective scheme for managingmulti-hop communications in infrastructure-based wireless communicationnetworks.

According to one embodiment of the invention, a wireless communicationsystem capable of managing multi-hop communications is provided. In thisembodiment, upon receiving a request from an originating mobile terminalfor initiating a call to a receiving mobile terminal, the systemdetermines whether the originating mobile terminal can use multi-hopcommunication services and an operating mode of the originating mobileterminal for multi-hop communication. The system also determines whetherrelaying can be provided by one or more relaying mobile terminals formulti-hop communication by the originating mobile terminal. If theoriginating mobile terminal can use the multi-hop communicationservices, the originating mobile terminal is in the default mode, andthe relaying can be provided, the system establishes multi-hopcommunication between the originating mobile terminal and the system. Onthe other hand, if the originating mobile terminal is in a prompt modefor multi-hop communication, the system sends a prompt to theoriginating mobile terminal for selection of the multi-hop communicationservices, along with information about incentives for using theservices. If it selects the multi-hop communication services, the systemallocates resources for setting up a multi-hop communication linkbetween the originating mobile terminal and the system.

After the multi-hop communication is completed, the system recordsinformation relating to the multi-hop communication services for theoriginating and relaying mobile terminals in at least one of a homelocation register and a visitor location register. The system also sendsdiscounted billing information to the originating mobile terminal andincentive information to the relaying mobile terminals.

Other objects and attainments together with a fuller understanding ofthe invention will become apparent and appreciated by referring to thefollowing description and claims taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in further detail, and by way of example,with reference to the accompanying drawings wherein:

FIG. 1 shows an overview of multi-hop communication in aninfrastructure-based, multi-hop enabled wireless communication network,according to one embodiment of the invention;

FIG. 2 illustrates a process performed by a wireless communicationnetwork for managing multi-hop communications, according to oneembodiment of the invention;

FIG. 3 illustrates a process performed by a mobile terminal forproviding relaying to another mobile terminal in multi-hopcommunication, according to one embodiment of the invention; and

FIG. 4 illustrates basic components of a mobile terminal in accordancewith one embodiment of the invention.

Throughout the drawings, the same reference numerals indicate similar orcorresponding features or functions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an overview of multi-hop communication in aninfrastructure-based, multi-hop enabled wireless communication network(e.g., a Universal Terrestrial Radio Access Network (UTRAN) and a 3 GPPcore network), according to one embodiment of the invention. The UTRANcomprises a radio network controller (RNC) 10 responsible for radioresource allocation and management and a Node B 16, which is a basestation transceiver. The UTRAN is connected to a core network (CN) 20,which is responsible for high layer signaling and data interaction. HomeLocation Register (HLR) and Visitor Location Register (VLR) 26 typicallylocated in CN 20 are responsible for recording information about mobileusers and related services.

A mobile terminal 31 or user equipment UE1 communicates with Node B 16with the relaying provided by mobile terminals 32 and 33 (UE2 and UE3).In this example, the direct link between the source and destination isbroken into 3 hops. Therefore, 3 radio resource units are needed tomaintain the basic communication between UE1 and Node B 16. Moredetailed descriptions of the multi-hop communication in aninfrastructure-based wireless communication network are provided in anarticle entitled “Self-organisation in Future Mobile Communications” byA. G. Spilling, A. R. Nix, M. A. Beach and T. J. Harrold, published byElectronic and Communication Engineering Journal in June 2000, and alsoin an article entitled “Intelligent Relaying for Future PersonalCommunication Systems” by T. J. Harrold and A. R. Nix, published by theInstitution of Electrical Engineers (IEE) in 2000. The disclosures ofthese two articles are hereby incorporated by reference.

FIG. 2 illustrates a process 100 performed by a wireless communicationsystem, e.g., a UTRAN, for managing multi-hop communications, accordingto one embodiment of the invention. The various steps of process 100 arepreferably implemented with software modules.

After a user has switched on a UE, the UE searches in a cell for signalsfrom the UTRAN, via a Broadcasting Control Channel (BCCH). The UTRANwill receive updated registration information from the UE (step S102).If the user has already subscribed multi-hop communication services, theuser can set (or preset) an operating mode for the multi-hopcommunication services as either a default mode or a prompt mode. In thedefault mode, when the UE originates a call, the multi-hop communicationservices are automatically selected as a first choice for communication.On the other hand, in the prompt mode, when the UE originates a call,the UE will receive a prompt from the UTRAN for selecting the multi-hopcommunication services. Each of the two modes may be set for a specifictime duration.

When the UE originates a call, it first sends a request to the UTRAN toinitiate the call. The request may include a multi-hop connect request.After receiving the request to initiate the call (step S106), the UTRANmay also automatically attempt to set up a multi-hop communication linkbetween the originating UE and itself, regardless of whether there is amulti-hop connect request from the UE. The UTRAN will first checkwhether the UE has subscribed the mutli-hop communication services (stepS108). Then, the UTRAN determines whether the UE is suitable for usingthe multi-hop communication services (step S112). If the UE is notsuitable because of, for example, the UE is not within a multi-hopcommunication supported radio range or one of the communicating UEs ismoving at a high speed, then the UTRAN will provide the conventionalcommunication services to the UE (step 114).

On the other hand, if the UE is suitable for using the multi-hopcommunication services, the UTRAN will determine whether the UE is in adefault or prompt mode for the multi-hop communication services (stepS116). If the UE is in the prompt mode, the UTRAN sends a prompt to theUE, along with information about the incentive to encourage the user touse the multi-hop communication services (step S122). The incentive maybe in the form of a discount, a rebate or promotional coupons, andinclude information about battery savings as a result of using multi-hopcommunication services. The discount may be calculated based on thestatistical benefits resulting from the system capacity increase and theoverall interference decrease. The discount rate may also be calculatedbased on the number of hops supporting the communication link. The morethe number of hops is used, the more the system capacity is increased.Additionally, the discount rate may vary in accordance with the actualtraffic load conditions or the interference during a predetermined timeduration. For example, if the traffic load is very heavy, the discountrate for the multi-hop communication services may be higher.

After the UTRAN receives a selection from the UE (step S126), itdetermines whether the UE has selected the multi-hop communicationservices (step S132). If the UE fails to select the multi-hopcommunication services because of the QoS (Quality of Service) concernsin the case of an important call for example, the UTRAN will provide theUE with the conventional communication services (step S114). On theother hand, if the UE has selected the multi-hop communication servicesor the UE is already in the default mode for using the multi-hopcommunication services, the UTRAN will determine whether multi-hoprelaying by other UEs is available for completing the call (step S134)and send information about incentive for providing relaying to theavailable UEs. If relaying is not available, the UTRAN will provide theconventional communication services to the UE (step S114). Otherwise,the UTRAN allocates resources to the originating and relaying UEs toallow the UE to start the multi-hop communication with the UTRAN (stepS136).

After the multi-hop communication is completed and the multi-hopcommunication resources are released, the UTRAN records the informationrelating to the multi-hop communication services for both theoriginating and relaying UEs in a Home Location Register (HLR) or aVisitor Location Register (VLR) (step S142). The UTRAN also sends thediscounted billing information to the originating UE and incentiveinformation to the relaying UEs to allow the users to immediately viewthe information (step S146).

The UTRAN performs steps similar to those in FIG. 2 for determiningwhether multi-hop communication services should be provided to areceiving UE.

FIG. 3 illustrates a process 200 performed by a UE for providingrelaying to another UE in multi-hop communication, according to oneembodiment of the invention. The various steps of process 200 arepreferably implemented with software modules.

After a user has switched on a UE (step S202), the UE searches in a cellfor signals from the UTRAN, via a Broadcasting Control Channel (BCCH).The user can set (or preset) a relaying mode as a default relaying mode,a prompt relaying mode or a disabled relaying mode for providingrelaying to other UEs in multi-hop communications (step S206). In thedefault relaying mode, the UE automatically provides relaying servicesupon receiving a request from the UTRAN. In the prompt relaying mode,however, the UE will receive a prompt from the UTRAN for decidingwhether or not to provide relaying services. In the disabled relayingmode, the UE is disabled from providing relaying services. Each of thesethree relaying modes can be set for a predetermined time duration.

Then the UE sends updated registration information to the UTRAN,including information about whether the UE is in a virtual switched-offmode or an idle mode (step S212). In the virtual switched-off mode, theUE is powered on but cannot originate or receive calls, and the networkcan make use of the UE for relaying in multi-hop communication withoutthe user's knowledge. Thus, a mobile user can have the UE turned off(e.g., during sleeping), but the UE can be used for providing relayingservices in multi-hop communications and earn money for the user. In theidle mode, the UE can originate and receive calls, and provide relayingfor multi-hop communications.

The UE checks whether itself is in a disabled relaying mode (step S214).If it is in the disabled mode, the UE rejects all requests for relayingservices. If it is not in a disabled relaying mode, the UE checks to seeif there is a request for relaying (step S226). If no request isreceived, the UE determines whether itself is in a default relaying modeor a prompt relaying mode (step S232). If it is in the default relayingmode, the UE responds to the UTRAN and provides relaying as requested(step S236). On the other hand, if the UE is in the prompt relayingmode, the UE receives a prompt from the UTRAN (step S242), along withinformation about incentive for providing relaying. The incentive may bein the form of redeemable points based on the time duration during whichthe relaying is provided. The UE then determines whether the user haschosen to provide relaying in multi-hop communication (step S246). Ifso, the UE will respond to the UTRAN and provide relaying as requested(step S236).

In the case of an emergency call that may be indicated by a specialsignal, forwarding the emergency call should be mandatory and defaultfor all mobile terminals that have subscribed multi-hop communicationservices as users or registered for providing relaying services inmulti-hop communications. The wireless communication system will processemergency calls on a first-come-first-serve basis.

In FIGS. 2 and 3 above, the various steps may be implemented withsoftware modules or a combination of software and hardware modules. In apreferred embodiment of the invention, the hardware of the existingUTRAN and UEs remains unchanged, while the various steps in FIGS. 2 and3 are all implemented with software modules.

FIG. 4 illustrates basic components of a mobile terminal 300 inaccordance with one embodiment of the invention. Mobile terminal 300includes an antenna 301, a RF unit 302, a baseband processor 306, amemory 312, a data processing unit 316, and a man-machine interface(MMI) 322. MMI 322 is typically in the form of a menu on a display andincludes a virtual switched-off indicator 324 that shows whether thevirtual switched-off mode of mobile terminal 300 is activated.

In the above, the invention has been illustrated in conjunction with aUTRAN. However, it is not limited to the UTRAN. In fact, any wirelessnetwork system may be used in conjunction with the present invention.

While the invention has been described in conjunction with specificembodiments, it is evident that many alternatives, modifications andvariations will be apparent to those skilled in the art in light of theforegoing description. Accordingly, it is intended to embrace all suchalternatives, modifications and variations as fall within the spirit andscope of the appended claims.

1. A method performed by a wireless communication system for managingmulti-hop communications, the method comprising the steps of: (a)receiving a request from an originating mobile terminal for initiating acall to a receiving mobile terminal; (b) determining whether theoriginating mobile terminal can use multi-hop communication services;(c) determining an operating mode of the originating mobile terminal formulti-hop communication; (d) determining whether relaying can beprovided by one or more relaying mobile terminals for multi-hopcommunication by the originating mobile terminal; and (e) if theoriginating mobile terminal can use the services, the originating mobileterminal is in the default mode, and the relaying can be provided,establishing multi-hop communication between the originating mobileterminal and the system.
 2. The method of claim 1, wherein step (b)includes the steps of: (i) determining whether the originating mobileterminal has subscribed multi-hop communication services; and (ii) ifthe originating mobile terminal has subscribed the multi-hopcommunication services, determining whether the originating mobileterminal is suitable for using the multi-hop communication services. 3.The method of claim 1, further comprising the step of: if theoriginating mobile terminal is in a prompt mode for multi-hopcommunication, sending a prompt to the originating mobile terminal forselection of the multi-hop communication services, along withinformation about incentives for using the services.
 4. The method ofclaim 3, wherein step (e) includes the step of: if the originatingmobile terminal in the prompt mode selects the multi-hop communicationservices, allocating resources for setting up a multi-hop communicationlink between the originating mobile terminal and the system.
 5. Themethod of claim 1, further comprising the step of: after the multi-hopcommunication is completed, recording information relating to themulti-hop communication services for the originating and relaying mobileterminals in at least one of a home location register and a visitorlocation register.
 6. The method of claim 5, further comprising the stepof: after the multi-hop communication is completed, sending discountedbilling information to the originating mobile terminal and incentiveinformation to the relaying mobile terminals.
 7. The method of claim 3,further comprising the step of providing conventional communicationservices to the originating mobile terminal, if the originating mobileterminal cannot use multi-hop communication services, the relayingcannot be provided, or the originating mobile terminal in the promptmode fails to select the multi-hop communication services.
 8. The methodof claim 3, further comprising the step of calculating the incentives tothe originating mobile terminal based on statistical benefits resultingfrom at least one of an increase in system capacity and an decrease inoverall interference.
 9. The method of claim 3, further comprising thestep of calculating the incentives to the originating mobile terminalbased on the number of hops used to support the multi-hop communicationlink.
 10. The method of claim 3, further comprising the step ofcalculating the incentives to the originating mobile terminal inaccordance with actual traffic load conditions and interference for apredetermined time duration.
 11. A method performed by a wirelesscommunication system in response to a request from an originating mobileterminal for initiating a call to a receiving mobile terminal, themethod comprising the steps of: (a) determining whether the receivingmobile terminal can use multi-hop communication services; (b)determining an operating mode of the receiving mobile terminal formulti-hop communication; (c) determining whether relaying can beprovided by one or more relaying mobile terminals for multi-hopcommunication by the receiving mobile terminal; and (d) if the receivingmobile terminal can use the services, the receiving mobile terminal isin the default mode, and the relaying can be provided, establishingmulti-hop communication between the receiving mobile terminal and thesystem.
 12. The method of claim 11, wherein step (a) includes the stepsof: (i) determining whether the receiving mobile terminal has subscribedmulti-hop communication services; and (ii) if the receiving mobileterminal has subscribed the multi-hop communication services,determining whether the receiving mobile terminal is suitable for usingthe multi-hop communication services.
 13. The method of claim 11,further comprising the step of: if the receiving mobile terminal is in aprompt mode for multi-hop communication, sending a prompt to thereceiving mobile terminal for selection of the multi-hop communicationservices, along with information about incentives for using theservices.
 14. The method of claim 13, wherein step (d) includes the stepof: if the receiving mobile terminal in the prompt mode selects themulti-hop communication services, allocating resources for setting up amulti-hop communication link between the receiving mobile terminal andthe system.
 15. The method of claim 11, further comprising the step of:after the multi-hop communication is completed, recording informationrelating to the multi-hop communication services for the receiving andrelaying mobile terminals in at least one of a home location registerand a visitor location register.
 16. The method of claim 15, furthercomprising the step of: after the multi-hop communication is completed,sending discounted billing information to the receiving mobile terminaland incentive information to the relaying mobile terminals.
 17. Themethod of claim 13, further comprising the step of providingconventional communication services to the receiving mobile terminal, ifthe receiving mobile terminal cannot use multi-hop communicationservices, the relaying cannot be provided, or the receiving mobileterminal in the prompt mode fails to select the multi-hop communicationservices.
 18. The method of claim 13, further comprising the step ofcalculating the incentives to the receiving mobile terminal based onstatistical benefits resulting from at least one of an increase insystem capacity and an decrease in overall interference.
 19. The methodof claim 13, further comprising the step of calculating the incentivesto the receiving mobile terminal based on the number of hops used tosupport the multi-hop communication link.
 20. The method of claim 13,further comprising the step of calculating the incentives to thereceiving mobile terminal in accordance with actual traffic loadconditions and interference for a predetermined time duration.
 21. Amethod performed by a mobile terminal, comprising the steps of: (a)checking whether there is a request from a wireless communication systemfor providing relaying in multi-hop communication; (b) if there is arequest for relaying, determining a relaying mode of the mobile terminalfor multi-hop communication; (c) if the mobile terminal is in a promptrelaying mode, checking whether a prompt for relaying has been receivedfrom the wireless communication system; (d) if the prompt has beenreceived, determining whether a user of the mobile terminal has chosento provide relaying; and (e) if the user has chosen to provide therelaying, providing the relaying.
 22. The method of claim 21, furthercomprising the step of, if the mobile terminal is in a default mode,providing the relaying.
 23. The method of claim 21, further comprisingthe step of, before step (a), checking whether the mobile terminal is inan idle mode; and wherein step (a) is performed if the mobile terminalis in an idle mode.
 24. The method of claim 21, further comprising thesteps of: before step (a) determining whether the mobile terminal is ina disabled relaying mode; and if the mobile terminal is in the disabledrelaying mode, rejecting any request for relaying.
 25. A wirelesscommunication system capable of managing multi-hop communications,comprising: means for receiving a request from an originating mobileterminal for initiating a call to a receiving mobile terminal; means fordetermining whether the originating mobile terminal can use multi-hopcommunication services; means for determining an operating mode of theoriginating mobile terminal for multi-hop communication; means fordetermining whether relaying can be provided by one or more relayingmobile terminals for multi-hop communication by the originating mobileterminal; and means for establishing multi-hop communication between theoriginating mobile terminal and the system; wherein the establishingmeans establishes the multi-hop communication if the originating mobileterminal can use the services, the originating mobile terminal is in thedefault mode, and the relaying can be provided.
 26. The system of claim25, wherein whether the originating mobile terminal can use multi-hopcommunication services is determined based on whether the originatingmobile terminal has subscribed multi-hop communication services andwhether the originating mobile terminal is suitable for using themulti-hop communication services.
 27. The system of claim 25, furthercomprising means for sending; wherein if the originating mobile terminalis in a prompt mode for multi-hop communication, the sending means sendsa prompt to the originating mobile terminal for selection of themulti-hop communication services, along with information aboutincentives for using the services.
 28. The system of claim 27, whereinthe establishing means includes means for allocating resources, andwherein if the originating mobile terminal in the prompt mode selectsthe multi-hop communication services, the allocating means allocatesresources for setting up a multi-hop communication link between theoriginating mobile terminal and the system.
 29. The system of claim 25,further comprising means for recording; wherein after the multi-hopcommunication is completed, the recording means records informationrelating to the multi-hop communication services for the originating andrelaying mobile terminals in at least one of a home location registerand a visitor location register.
 30. The system of claim 27, whereinafter the multi-hop communication is completed, the sending means sendsdiscounted billing information to the originating mobile terminal andincentive information to the relaying mobile terminals.
 31. The systemof claim 27, further comprising means for calculating the incentives tothe originating mobile terminal based on statistical benefits resultingfrom at least one of an increase in system capacity and an decrease inoverall interference.
 32. The system of claim 27, further comprisingmeans for calculating the incentives to the originating mobile terminalbased on the number of hops used to support the multi-hop communicationlink.
 33. The system of claim 25, wherein the three determining meansrespectively determines: whether the receiving mobile terminal can usemulti-hop communication services; an operating mode of the receivingmobile terminal for multi-hop communication; and whether relaying can beprovided by one or more relaying mobile terminals for multi-hopcommunication by the receiving mobile terminal; and wherein theestablishing means establishes the multi-hop communication between thereceiving mobile terminal and the system if the receiving mobileterminal can use the services, the receiving mobile terminal is in thedefault mode, and the relaying can be provided.